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Reinstated interrupts by moving the refresh test back into the refresh cycle.

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This commit is contained in:
Thomas Harte 2017-06-21 21:03:39 -04:00
parent 0e0ce379b4
commit 4bf13610ce
1 changed files with 13 additions and 3 deletions
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16
Machines/ZX8081/ZX8081.cpp
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@ -57,6 +57,10 @@ int Machine::perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
// tape_player_.run_for_cycles(cycle.length + wait_cycles);
if(!cycle.is_terminal()) {
return wait_cycles;
}
uint16_t refresh = 0;
uint16_t address = cycle.address ? *cycle.address : 0;
bool is_opcode_read = false;
@ -91,15 +95,21 @@ int Machine::perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
horizontal_counter_ = 0;
break;
case CPU::Z80::PartialMachineCycle::Refresh:
if(!(address & 0x40)) {
set_interrupt_line(true, -2);
set_interrupt_line(false);
}
break;
case CPU::Z80::PartialMachineCycle::ReadOpcodeStart:
case CPU::Z80::PartialMachineCycle::ReadOpcodeWait:
// printf("%04x ", address);
// The ZX80 and 81 signal an interrupt while refresh is active and bit 6 of the refresh
// address is low. The Z80 signals a refresh, providing the refresh address during the
// final two cycles of an opcode fetch. Therefore communicate a transient signalling
// of the IRQ line if necessary.
refresh = get_value_of_register(CPU::Z80::Register::Refresh);
set_interrupt_line(!(refresh & 0x40), -2);
set_interrupt_line(false);
// refresh = get_value_of_register(CPU::Z80::Register::Refresh);
// Check for use of the fast tape hack.
if(address == tape_trap_address_) { // TODO: && fast_tape_hack_enabled_